• Definitions
• Key roles of robustness analysis
• Closer look at object types
  • Boundary objects
  • Entity objects
  • Control objects
• Performing robustness analysis
  • .

Robustness analysis

Robustness analysis involves:

1. analyzing the text of each of your use cases,
2. identify a first-guess set of objects that will participate in the use case, then
3. classify these objects into
   1. Boundary objects
   2. Entity objects
   3. Control objects
4. This has parallels in the Model/View/Controller paradigm.

Definitions

• Boundary objects - Actors use these to communicate with the system ("View").
• Entity objects - Usually objects from the problem domain ("Model").
• Control objects - Serve as the "glue" between Boundary and Entity objects ("Controller").

Key roles of robustness analysis

• Sanity check - make sure your use case text is correct.
• Completeness check - make sure your use cases address all the necessary alternate courses of action.
• Ongoing discovery of objects - you may have missed some objects during domain modeling.

Closer look at object types

Boundary objects

• "View".
• Objects that the Actors will be interacting with.
• Windows, screens, dialogs, menus.
• Get many from prototypes.

Entity objects

• "Model".
• Often map to database tables and files.
• Many come from the domain model.
• Simpler and more generic - easier to reuse in other projects.

Control objects

• "Controller".
• Embody much of the application logic.
• Where you capture business rules and application logic.
• Not necessarily meant to endure as stand-alone classes as you proceed.
• Sometimes serve as placeholders to make sure you don't forget any functionality and system behavior required by your uses cases.

Performing robustness analysis

• Actors can talk only to Boundary objects.
• Boundary objects can talk only to Controllers and Actors.
• Entity objects can only talk to Controllers.
• Controllers can talk to both Boundary objects and Controllers, but not to Actors.
• Update your static model.

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